BS 970 (Part 3):1991 826M31 Steel: Specifications & Listings

Maximum unless a range is stated.

Source: BS 970 (Part 3):1991, Table 16

Condition	Reference symbol	Size (mm)	Tensile strength Rm (MPa)	Yield Re, min (MPa)	Elongation, min (%)	Impact Izod, min (J)	Impact KCV, min (J)	Rp0.2, min (MPa)	Hardness HB	Notes
Hardened and tempered and turned or ground	T	> 150 ≤ 250	850-1000	650	13	40	35	635	248-302
Hardened and tempered and turned or ground	T	> 100 ≤ 150	850-1000	680	13	54	50	665	248-302
Hardened and tempered and turned or ground	U	> 150 ≤ 250	925-1075	740	12	34	28	725	269-331
Hardened and tempered and turned or ground	U	> 100 ≤ 150	925-1075	755	12	47	42	740	269-331
Hardened and tempered and turned or ground	V	> 63 ≤ 150	1000-1150	850	12	47	42	835	293-352
Hardened and tempered and turned or ground	W	> 29 ≤ 100	1075-1225	940	11	40	35	925	311-375	(6)
Hardened and tempered and turned or ground	X	> 13 ≤ 63	1150-1300	1020	10	34	28	1005	341-401	(6)
Hardened and tempered and turned or ground	Z	> 13 ≤ 63	1550 min.	1235	5	10	9	1125	444 min.	(6)
Hardened and tempered and cold drawn or hardened and tempered and cold drawn and ground	T	> 63 ≤ 150	850-1000	700	9	54	—	680	248-302
Hardened and tempered and cold drawn or hardened and tempered and cold drawn and ground	U	> 29 ≤ 100	925-1075	770	9	47	—	755	269-331
Hardened and tempered and cold drawn or hardened and tempered and cold drawn and ground	V	> 29 ≤ 150	1000-1150	885	9	47	—	850	293-362
Hardened and tempered and cold drawn or hardened and tempered and cold drawn and ground	W	> 29 ≤ 100	1075-1225	955	8	40	—	940	311-375	(4)(6)(7)
Hardened and tempered and cold drawn or hardened and tempered and cold drawn and ground	X	> 6 ≤ 63	1150-1300	1035	7	34	—	1020	341-401	(4)(6)(7)
Hardened and tempered and cold drawn or hardened and tempered and cold drawn and ground	Z	> 6 ≤ 63	1550 min.	1250	3	10	—	1235	444 min.	(4)(6)(7)
Turned, ground or cold drawn and finally softened		—	—	—	—	—	—	—	277 max.

Condition letters P to Z are the tensile strength ranges of Table 29. Rp0.2 applies when specifically ordered (note 3). Hardness HB is for guidance only except in the softened condition (note 13). Impact: Izod, or KCV when the standard impact test is not required (option A.3). Note 6: Often ordered in the softened condition for machining and subsequent heat treatment to achieve these mechanical properties. Note 6: Often ordered in the softened condition for machining and subsequent heat treatment to achieve these mechanical properties. Note 6: Often ordered in the softened condition for machining and subsequent heat treatment to achieve these mechanical properties. Note 4: These properties cannot always be obtained by bulk heat treatment of bar but can be achieved by the appropriate heat treatment of components by the purchaser. Note 6: Often ordered in the softened condition for machining and subsequent heat treatment to achieve these mechanical properties. Note 7: Cold drawn bars are not normally available in this tensile strength range. Note 4: These properties cannot always be obtained by bulk heat treatment of bar but can be achieved by the appropriate heat treatment of components by the purchaser. Note 6: Often ordered in the softened condition for machining and subsequent heat treatment to achieve these mechanical properties. Note 7: Cold drawn bars are not normally available in this tensile strength range. Note 4: These properties cannot always be obtained by bulk heat treatment of bar but can be achieved by the appropriate heat treatment of components by the purchaser. Note 6: Often ordered in the softened condition for machining and subsequent heat treatment to achieve these mechanical properties. Note 7: Cold drawn bars are not normally available in this tensile strength range.

Source: BS 970 (Part 3):1991, Table 21